Concerning or overthinking?

My boyfriend and I were on the phone and he was talking about his neck poping/breaking, me being the dirty minded and a goofy person, I made a flirtatious joke saying "you can break my back" you know just playing around and he sorta just throws it off with things like "if I break your back you'd glow cause you're a glow stick" or just random things that shows hes not really interested. Which I was messing around in the first place but it makes me wonder if I have made him uncomfortable... when we're in person he'll flirt and make jokes, bend me over and pretend to *u** me 😂 but for awhile now he's stopped flirting back or making jokes over the phone. Am I just overthinking? I asked if his feelings have changed and he told me "baby you know they haven't". Maybe he's just growing up and doesn't want to joke like that anymore? Idk. What do yall think?